Flea Treatment quandary please help

[Thiscantbetrue]

So my Cats (6 of them) have fleas & I purchased the Advantage flea stuff for them , on the front of the box it states it's for cats and small dogs yet I have just read that dog flea treatment is dangerous to cats & not to use it on cats under any circumstances
so why does it say for cats and dogs?
Is it harmful to cats or is it just a case of the dosage been different which is the danger ?
why would dog treatment be different to cats when it's treating the same thing ?
Sorry I seem rather clueless but it's the first time I will be using advantage as Frontline stopped working on my cats

[thecatneuterer]

It depends on the product. Advantage can be used on either cats or dogs - only the dosage varies. Other products intended for dogs (eg Bob Martin) must never be used on cats. In fact I think Advantage is the only interchangeable one.

[Fluffycloudland77]

A small dog and a cat can weigh a similar amount which is important for the maximum safe dose of a product.

If its safe for both species then its just to make sure no Rottweiler owners use it and wonder why they still have a flea problem.

[Thiscantbetrue]

Thank you